[llvm] 2663a25 - [JumpThreading] Half the duplicate threshold at Oz
Sam Parker via llvm-commits
llvm-commits at lists.llvm.org
Mon Feb 3 00:40:34 PST 2020
Author: Sam Parker
Date: 2020-02-03T08:40:20Z
New Revision: 2663a25fadf73e0992182caf4871161a142515ad
URL: https://github.com/llvm/llvm-project/commit/2663a25fadf73e0992182caf4871161a142515ad
DIFF: https://github.com/llvm/llvm-project/commit/2663a25fadf73e0992182caf4871161a142515ad.diff
LOG: [JumpThreading] Half the duplicate threshold at Oz
Duplicating instructions can lead to code size increases but using
a threshold of 3 is good for reducing code size.
Differential Revision: https://reviews.llvm.org/D72916
Added:
llvm/test/Transforms/JumpThreading/codesize-loop.ll
Modified:
llvm/include/llvm/Transforms/Scalar/JumpThreading.h
llvm/lib/Transforms/Scalar/JumpThreading.cpp
Removed:
################################################################################
diff --git a/llvm/include/llvm/Transforms/Scalar/JumpThreading.h b/llvm/include/llvm/Transforms/Scalar/JumpThreading.h
index a8beb8ca6e05..d9e69095a109 100644
--- a/llvm/include/llvm/Transforms/Scalar/JumpThreading.h
+++ b/llvm/include/llvm/Transforms/Scalar/JumpThreading.h
@@ -90,6 +90,7 @@ class JumpThreadingPass : public PassInfoMixin<JumpThreadingPass> {
#endif
unsigned BBDupThreshold;
+ unsigned DefaultBBDupThreshold;
public:
JumpThreadingPass(int T = -1);
diff --git a/llvm/lib/Transforms/Scalar/JumpThreading.cpp b/llvm/lib/Transforms/Scalar/JumpThreading.cpp
index 98c2fcb3dae0..f2b12af3c5fc 100644
--- a/llvm/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/llvm/lib/Transforms/Scalar/JumpThreading.cpp
@@ -170,7 +170,7 @@ FunctionPass *llvm::createJumpThreadingPass(int Threshold) {
}
JumpThreadingPass::JumpThreadingPass(int T) {
- BBDupThreshold = (T == -1) ? BBDuplicateThreshold : unsigned(T);
+ DefaultBBDupThreshold = (T == -1) ? BBDuplicateThreshold : unsigned(T);
}
// Update branch probability information according to conditional
@@ -374,6 +374,15 @@ bool JumpThreadingPass::runImpl(Function &F, TargetLibraryInfo *TLI_,
BFI = std::move(BFI_);
}
+ // Reduce the number of instructions duplicated when optimizing strictly for
+ // size.
+ if (BBDuplicateThreshold.getNumOccurrences())
+ BBDupThreshold = BBDuplicateThreshold;
+ else if (F.hasFnAttribute(Attribute::MinSize))
+ BBDupThreshold = 3;
+ else
+ BBDupThreshold = DefaultBBDupThreshold;
+
// JumpThreading must not processes blocks unreachable from entry. It's a
// waste of compute time and can potentially lead to hangs.
SmallPtrSet<BasicBlock *, 16> Unreachable;
diff --git a/llvm/test/Transforms/JumpThreading/codesize-loop.ll b/llvm/test/Transforms/JumpThreading/codesize-loop.ll
new file mode 100644
index 000000000000..68d6a99d86de
--- /dev/null
+++ b/llvm/test/Transforms/JumpThreading/codesize-loop.ll
@@ -0,0 +1,152 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -jump-threading -S %s -o - | FileCheck %s --check-prefix=DEFAULT
+; RUN: opt -jump-threading -S -jump-threading-threshold=6 %s -o - | FileCheck %s --check-prefix=OVERIDE
+
+ at .str = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
+define i32 @test_minsize(i32 %argc, i8** nocapture readonly %argv) local_unnamed_addr #0 {
+; DEFAULT-LABEL: @test_minsize(
+; DEFAULT-NEXT: entry:
+; DEFAULT-NEXT: [[CMP:%.*]] = icmp eq i32 [[ARGC:%.*]], 2
+; DEFAULT-NEXT: br i1 [[CMP]], label [[COND_TRUE:%.*]], label [[COND_END:%.*]]
+; DEFAULT: cond.true:
+; DEFAULT-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds i8*, i8** [[ARGV:%.*]], i32 1
+; DEFAULT-NEXT: [[TMP0:%.*]] = load i8*, i8** [[ARRAYIDX]], align 4
+; DEFAULT-NEXT: [[CALL:%.*]] = tail call i32 @atoi(i8* [[TMP0]])
+; DEFAULT-NEXT: br label [[COND_END]]
+; DEFAULT: cond.end:
+; DEFAULT-NEXT: [[COND:%.*]] = phi i32 [ [[CALL]], [[COND_TRUE]] ], [ 46, [[ENTRY:%.*]] ]
+; DEFAULT-NEXT: [[TMP1:%.*]] = mul i32 [[COND]], [[COND]]
+; DEFAULT-NEXT: [[TMP2:%.*]] = mul i32 [[TMP1]], [[TMP1]]
+; DEFAULT-NEXT: [[TMP3:%.*]] = mul i32 [[COND]], [[TMP2]]
+; DEFAULT-NEXT: [[TMP4:%.*]] = icmp sgt i32 [[COND]], 0
+; DEFAULT-NEXT: br i1 [[TMP4]], label [[TMP5:%.*]], label [[TMP6:%.*]]
+; DEFAULT: 5:
+; DEFAULT-NEXT: br label [[TMP6]]
+; DEFAULT: 6:
+; DEFAULT-NEXT: [[TMP7:%.*]] = phi i32 [ [[COND]], [[TMP5]] ], [ 0, [[COND_END]] ]
+; DEFAULT-NEXT: [[TMP8:%.*]] = mul i32 [[TMP3]], [[TMP7]]
+; DEFAULT-NEXT: [[CALL33:%.*]] = tail call i32 (i8*, ...) @printf(i8* nonnull dereferenceable(1) getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i32 0, i32 0), i32 [[TMP8]])
+; DEFAULT-NEXT: ret i32 0
+;
+; OVERIDE-LABEL: @test_minsize(
+; OVERIDE-NEXT: entry:
+; OVERIDE-NEXT: [[CMP:%.*]] = icmp eq i32 [[ARGC:%.*]], 2
+; OVERIDE-NEXT: br i1 [[CMP]], label [[COND_END:%.*]], label [[COND_END_THREAD:%.*]]
+; OVERIDE: cond.end:
+; OVERIDE-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds i8*, i8** [[ARGV:%.*]], i32 1
+; OVERIDE-NEXT: [[TMP0:%.*]] = load i8*, i8** [[ARRAYIDX]], align 4
+; OVERIDE-NEXT: [[CALL:%.*]] = tail call i32 @atoi(i8* [[TMP0]])
+; OVERIDE-NEXT: [[TMP1:%.*]] = mul i32 [[CALL]], [[CALL]]
+; OVERIDE-NEXT: [[TMP2:%.*]] = mul i32 [[TMP1]], [[TMP1]]
+; OVERIDE-NEXT: [[TMP3:%.*]] = mul i32 [[CALL]], [[TMP2]]
+; OVERIDE-NEXT: [[TMP4:%.*]] = icmp sgt i32 [[CALL]], 0
+; OVERIDE-NEXT: br i1 [[TMP4]], label [[COND_END_THREAD]], label [[TMP6:%.*]]
+; OVERIDE: cond.end.thread:
+; OVERIDE-NEXT: [[TMP5:%.*]] = phi i32 [ [[TMP3]], [[COND_END]] ], [ 205962976, [[ENTRY:%.*]] ]
+; OVERIDE-NEXT: [[COND2:%.*]] = phi i32 [ [[CALL]], [[COND_END]] ], [ 46, [[ENTRY]] ]
+; OVERIDE-NEXT: br label [[TMP6]]
+; OVERIDE: 6:
+; OVERIDE-NEXT: [[TMP7:%.*]] = phi i32 [ [[TMP5]], [[COND_END_THREAD]] ], [ [[TMP3]], [[COND_END]] ]
+; OVERIDE-NEXT: [[TMP8:%.*]] = phi i32 [ [[COND2]], [[COND_END_THREAD]] ], [ 0, [[COND_END]] ]
+; OVERIDE-NEXT: [[TMP9:%.*]] = mul i32 [[TMP7]], [[TMP8]]
+; OVERIDE-NEXT: [[CALL33:%.*]] = tail call i32 (i8*, ...) @printf(i8* nonnull dereferenceable(1) getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i32 0, i32 0), i32 [[TMP9]])
+; OVERIDE-NEXT: ret i32 0
+;
+entry:
+ %cmp = icmp eq i32 %argc, 2
+ br i1 %cmp, label %cond.true, label %cond.end
+
+cond.true: ; preds = %entry
+ %arrayidx = getelementptr inbounds i8*, i8** %argv, i32 1
+ %0 = load i8*, i8** %arrayidx, align 4
+ %call = tail call i32 @atoi(i8* %0)
+ br label %cond.end
+
+cond.end: ; preds = %entry, %cond.true
+ %cond = phi i32 [ %call, %cond.true ], [ 46, %entry ]
+ %1 = mul i32 %cond, %cond
+ %2 = mul i32 %1, %1
+ %3 = mul i32 %cond, %2
+ %4 = icmp sgt i32 %cond, 0
+ %spec.select = select i1 %4, i32 %cond, i32 0
+ %5 = mul i32 %3, %spec.select
+ %call33 = tail call i32 (i8*, ...) @printf(i8* nonnull dereferenceable(1) getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i32 0, i32 0), i32 %5) #4
+ ret i32 0
+}
+
+define i32 @test_optsize(i32 %argc, i8** nocapture readonly %argv) local_unnamed_addr #1 {
+; DEFAULT-LABEL: @test_optsize(
+; DEFAULT-NEXT: entry:
+; DEFAULT-NEXT: [[CMP:%.*]] = icmp eq i32 [[ARGC:%.*]], 2
+; DEFAULT-NEXT: br i1 [[CMP]], label [[COND_END:%.*]], label [[COND_END_THREAD:%.*]]
+; DEFAULT: cond.end:
+; DEFAULT-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds i8*, i8** [[ARGV:%.*]], i32 1
+; DEFAULT-NEXT: [[TMP0:%.*]] = load i8*, i8** [[ARRAYIDX]], align 4
+; DEFAULT-NEXT: [[CALL:%.*]] = tail call i32 @atoi(i8* [[TMP0]])
+; DEFAULT-NEXT: [[TMP1:%.*]] = mul i32 [[CALL]], [[CALL]]
+; DEFAULT-NEXT: [[TMP2:%.*]] = mul i32 [[TMP1]], [[TMP1]]
+; DEFAULT-NEXT: [[TMP3:%.*]] = mul i32 [[CALL]], [[TMP2]]
+; DEFAULT-NEXT: [[TMP4:%.*]] = icmp sgt i32 [[CALL]], 0
+; DEFAULT-NEXT: br i1 [[TMP4]], label [[COND_END_THREAD]], label [[TMP6:%.*]]
+; DEFAULT: cond.end.thread:
+; DEFAULT-NEXT: [[TMP5:%.*]] = phi i32 [ [[TMP3]], [[COND_END]] ], [ 205962976, [[ENTRY:%.*]] ]
+; DEFAULT-NEXT: [[COND2:%.*]] = phi i32 [ [[CALL]], [[COND_END]] ], [ 46, [[ENTRY]] ]
+; DEFAULT-NEXT: br label [[TMP6]]
+; DEFAULT: 6:
+; DEFAULT-NEXT: [[TMP7:%.*]] = phi i32 [ [[TMP5]], [[COND_END_THREAD]] ], [ [[TMP3]], [[COND_END]] ]
+; DEFAULT-NEXT: [[TMP8:%.*]] = phi i32 [ [[COND2]], [[COND_END_THREAD]] ], [ 0, [[COND_END]] ]
+; DEFAULT-NEXT: [[TMP9:%.*]] = mul i32 [[TMP7]], [[TMP8]]
+; DEFAULT-NEXT: [[CALL33:%.*]] = tail call i32 (i8*, ...) @printf(i8* nonnull dereferenceable(1) getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i32 0, i32 0), i32 [[TMP9]])
+; DEFAULT-NEXT: ret i32 0
+;
+; OVERIDE-LABEL: @test_optsize(
+; OVERIDE-NEXT: entry:
+; OVERIDE-NEXT: [[CMP:%.*]] = icmp eq i32 [[ARGC:%.*]], 2
+; OVERIDE-NEXT: br i1 [[CMP]], label [[COND_END:%.*]], label [[COND_END_THREAD:%.*]]
+; OVERIDE: cond.end:
+; OVERIDE-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds i8*, i8** [[ARGV:%.*]], i32 1
+; OVERIDE-NEXT: [[TMP0:%.*]] = load i8*, i8** [[ARRAYIDX]], align 4
+; OVERIDE-NEXT: [[CALL:%.*]] = tail call i32 @atoi(i8* [[TMP0]])
+; OVERIDE-NEXT: [[TMP1:%.*]] = mul i32 [[CALL]], [[CALL]]
+; OVERIDE-NEXT: [[TMP2:%.*]] = mul i32 [[TMP1]], [[TMP1]]
+; OVERIDE-NEXT: [[TMP3:%.*]] = mul i32 [[CALL]], [[TMP2]]
+; OVERIDE-NEXT: [[TMP4:%.*]] = icmp sgt i32 [[CALL]], 0
+; OVERIDE-NEXT: br i1 [[TMP4]], label [[COND_END_THREAD]], label [[TMP6:%.*]]
+; OVERIDE: cond.end.thread:
+; OVERIDE-NEXT: [[TMP5:%.*]] = phi i32 [ [[TMP3]], [[COND_END]] ], [ 205962976, [[ENTRY:%.*]] ]
+; OVERIDE-NEXT: [[COND2:%.*]] = phi i32 [ [[CALL]], [[COND_END]] ], [ 46, [[ENTRY]] ]
+; OVERIDE-NEXT: br label [[TMP6]]
+; OVERIDE: 6:
+; OVERIDE-NEXT: [[TMP7:%.*]] = phi i32 [ [[TMP5]], [[COND_END_THREAD]] ], [ [[TMP3]], [[COND_END]] ]
+; OVERIDE-NEXT: [[TMP8:%.*]] = phi i32 [ [[COND2]], [[COND_END_THREAD]] ], [ 0, [[COND_END]] ]
+; OVERIDE-NEXT: [[TMP9:%.*]] = mul i32 [[TMP7]], [[TMP8]]
+; OVERIDE-NEXT: [[CALL33:%.*]] = tail call i32 (i8*, ...) @printf(i8* nonnull dereferenceable(1) getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i32 0, i32 0), i32 [[TMP9]])
+; OVERIDE-NEXT: ret i32 0
+;
+entry:
+ %cmp = icmp eq i32 %argc, 2
+ br i1 %cmp, label %cond.true, label %cond.end
+
+cond.true: ; preds = %entry
+ %arrayidx = getelementptr inbounds i8*, i8** %argv, i32 1
+ %0 = load i8*, i8** %arrayidx, align 4
+ %call = tail call i32 @atoi(i8* %0)
+ br label %cond.end
+
+cond.end: ; preds = %entry, %cond.true
+ %cond = phi i32 [ %call, %cond.true ], [ 46, %entry ]
+ %1 = mul i32 %cond, %cond
+ %2 = mul i32 %1, %1
+ %3 = mul i32 %cond, %2
+ %4 = icmp sgt i32 %cond, 0
+ %spec.select = select i1 %4, i32 %cond, i32 0
+ %5 = mul i32 %3, %spec.select
+ %call33 = tail call i32 (i8*, ...) @printf(i8* nonnull dereferenceable(1) getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i32 0, i32 0), i32 %5) #4
+ ret i32 0
+}
+declare i32 @atoi(i8* nocapture) local_unnamed_addr
+declare i32 @printf(i8* nocapture readonly, ...) local_unnamed_addr
+
+attributes #0 = { minsize optsize }
+attributes #1 = { optsize }
+
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